1. FIELD OF THE INVENTION
This invention relates to methods for sealing capsules, using sealing fluids, and/or thermal energy; and apparatus for sealing such capsules.
The capsules sealed by utilizing the present invention are hard shell, telescopically joined capsules, having coaxial cap and body parts. The capsules are made of gelatin or other materials whose properties are pharmaceutically acceptable.
In this application, when the term "gelatin" is used it is also understood to include gelatin combined with other hydrophilic polymers.
Capsules were sealed having a cap and/or body part made from a gelatin foam as disclosed in applicant's copending application U.S. Ser. No. 438,147 filed Oct. 29, 1982, now abandoned, the disclosure of which is incorporated herein by reference.
In addition, capsules were sealed by sealing fluids as disclosed in applicant's copending application U.S. Ser. No. 451,580, filed Dec. 20, 1982, now abandoned, the disclosure of which is incorporated herein by reference.
Hard shell gelatin capsules have a disadvantage when compared with other dosage forms, in that the cap and the body parts can be opened and rejoined without the disruption becoming externally visible or tamper-evident. Therefore, the consumer has no real guarantee that the contents of a capsule have not been tampered with.
Telescopically joined, hard shell gelatin capsules have an overlap of the cap side wall over the body side wall which impedes gripping and withdrawal of the body, thereby making separation difficult. The present invention uses sealing fluid and/or thermal energy applied to the overlap of the cap side wall over the body side wall to secure tamper-proofing by spot or complete sealing of the overlap of the capsule parts. With the use of a complete sealing, the capsules are also tight against leakage of liquid contents.
2. DESCRIPTION OF THE PRIOR ART
Prior art for capsule sealing is contained in the following United States patents:
1. U.S. Pat. No. 3,071,513 issued Jan. 1, 1963 to H. R. De Boer, et al. which discloses a sealing fluid comprising a dispersion of an air-drying hydrophilic, film-forming polymer in an organic solvent. The application of the sealing fluid was by dipping the capsules:
2. U.S. Pat. No. 3,159,546 issued Dec. 1, 1974 to J. R. Kane discloses a liquid sealant consisting of three components containing by weight from about 1 to 41/2 parts, preferably 3 to 41/2 parts, of acetone; from about 11/2 to 2 parts, and preferably 11/4 to 2 parts, of water; and from about 3/4 to 21/4 parts, and preferably about 3/4 of a part, of ethyl acetate. The application of the liquid solvent was by drop application.